Merge bitcoin#20480: Replace boost::variant with std::variant

faa8f68 Replace boost::variant with std::variant (MarcoFalke)

Pull request description:

  Now that we can use std::variant from the vanilla standard library, drop the third-party boost variant dependency

ACKs for top commit:
  fjahr:
    Code review ACK faa8f68
  fanquake:
    ACK faa8f68

Tree-SHA512: 6e3aecd33b00c2e31a763f999247944d5b2ce5e3018f1965c516c1000cd08ff6703a8d50fb0be64883153da2925ae72986b8a6b96586db74057bd05d6f4986e6

Author: fanquake

src/key_io.cpp

@@ -8,16 +8,12 @@
 #include <bech32.h>
 #include <util/strencodings.h>
 
-#include <boost/variant/apply_visitor.hpp>
-#include <boost/variant/static_visitor.hpp>
-
+#include <algorithm>
 #include <assert.h>
 #include <string.h>
-#include <algorithm>
 
-namespace
-{
-class DestinationEncoder : public boost::static_visitor<std::string>
+namespace {
+class DestinationEncoder
 {
 private:
     const CChainParams& m_params;
@@ -209,7 +205,7 @@ std::string EncodeExtKey(const CExtKey& key)
 
 std::string EncodeDestination(const CTxDestination& dest)
 {
-    return boost::apply_visitor(DestinationEncoder(Params()), dest);
+    return std::visit(DestinationEncoder(Params()), dest);
 }
 
 CTxDestination DecodeDestination(const std::string& str)

src/qt/addresstablemodel.cpp

@@ -11,7 +11,6 @@
 #include <wallet/wallet.h>
 
 #include <algorithm>
-#include <typeinfo>
 
 #include <QFont>
 #include <QDebug>
@@ -82,8 +81,9 @@ class AddressTablePriv
         {
             for (const auto& address : wallet.getAddresses())
             {
-                if (pk_hash_only && address.dest.type() != typeid(PKHash))
+                if (pk_hash_only && !std::holds_alternative<PKHash>(address.dest)) {
                     continue;
+                }
                 AddressTableEntry::Type addressType = translateTransactionType(
                         QString::fromStdString(address.purpose), address.is_mine);
                 cachedAddressTable.append(AddressTableEntry(addressType,
@@ -261,7 +261,7 @@ bool AddressTableModel::setData(const QModelIndex &index, const QVariant &value,
         } else if(index.column() == Address) {
             CTxDestination newAddress = DecodeDestination(value.toString().toStdString());
             // Refuse to set invalid address, set error status and return false
-            if(boost::get<CNoDestination>(&newAddress))
+            if(std::get_if<CNoDestination>(&newAddress))
             {
                 editStatus = INVALID_ADDRESS;
                 return false;

src/qt/coincontroldialog.cpp

@@ -455,7 +455,7 @@ void CoinControlDialog::updateLabels(CCoinControl& m_coin_control, WalletModel *
         else if(ExtractDestination(out.txout.scriptPubKey, address))
         {
             CPubKey pubkey;
-            PKHash *pkhash = boost::get<PKHash>(&address);
+            PKHash* pkhash = std::get_if<PKHash>(&address);
             if (pkhash && model->wallet().getPubKey(out.txout.scriptPubKey, ToKeyID(*pkhash), pubkey))
             {
                 nBytesInputs += (pubkey.IsCompressed() ? 148 : 180);

src/qt/signverifymessagedialog.cpp

@@ -120,7 +120,7 @@ void SignVerifyMessageDialog::on_signMessageButton_SM_clicked()
         ui->statusLabel_SM->setText(tr("The entered address is invalid.") + QString(" ") + tr("Please check the address and try again."));
         return;
     }
-    const PKHash* pkhash = boost::get<PKHash>(&destination);
+    const PKHash* pkhash = std::get_if<PKHash>(&destination);
     if (!pkhash) {
         ui->addressIn_SM->setValid(false);
         ui->statusLabel_SM->setStyleSheet("QLabel { color: red; }");

src/qt/transactionrecord.cpp

@@ -123,7 +123,7 @@ QList<TransactionRecord> TransactionRecord::decomposeTransaction(const interface
                     continue;
                 }
 
-                if (!boost::get<CNoDestination>(&wtx.txout_address[nOut]))
+                if (!std::get_if<CNoDestination>(&wtx.txout_address[nOut]))
                 {
                     // Sent to Bitcoin Address
                     sub.type = TransactionRecord::SendToAddress;

src/rpc/util.cpp

@@ -209,7 +209,7 @@ CTxDestination AddAndGetMultisigDestination(const int required, const std::vecto
     return dest;
 }
 
-class DescribeAddressVisitor : public boost::static_visitor<UniValue>
+class DescribeAddressVisitor
 {
 public:
     explicit DescribeAddressVisitor() {}
@@ -267,7 +267,7 @@ class DescribeAddressVisitor : public boost::static_visitor<UniValue>
 
 UniValue DescribeAddress(const CTxDestination& dest)
 {
-    return boost::apply_visitor(DescribeAddressVisitor(), dest);
+    return std::visit(DescribeAddressVisitor(), dest);
 }
 
 unsigned int ParseConfirmTarget(const UniValue& value, unsigned int max_target)

src/script/descriptor.cpp

@@ -565,7 +565,7 @@ class AddressDescriptor final : public DescriptorImpl
 
     Optional<OutputType> GetOutputType() const override
     {
-        switch (m_destination.which()) {
+        switch (m_destination.index()) {
             case 1 /* PKHash */:
             case 2 /* ScriptHash */: return OutputType::LEGACY;
             case 3 /* WitnessV0ScriptHash */:
@@ -593,7 +593,7 @@ class RawDescriptor final : public DescriptorImpl
     {
         CTxDestination dest;
         ExtractDestination(m_script, dest);
-        switch (dest.which()) {
+        switch (dest.index()) {
             case 1 /* PKHash */:
             case 2 /* ScriptHash */: return OutputType::LEGACY;
             case 3 /* WitnessV0ScriptHash */:

src/script/signingprovider.cpp

@@ -179,18 +179,18 @@ CKeyID GetKeyForDestination(const SigningProvider& store, const CTxDestination&
 {
     // Only supports destinations which map to single public keys, i.e. P2PKH,
     // P2WPKH, and P2SH-P2WPKH.
-    if (auto id = boost::get<PKHash>(&dest)) {
+    if (auto id = std::get_if<PKHash>(&dest)) {
         return ToKeyID(*id);
     }
-    if (auto witness_id = boost::get<WitnessV0KeyHash>(&dest)) {
+    if (auto witness_id = std::get_if<WitnessV0KeyHash>(&dest)) {
         return ToKeyID(*witness_id);
     }
-    if (auto script_hash = boost::get<ScriptHash>(&dest)) {
+    if (auto script_hash = std::get_if<ScriptHash>(&dest)) {
         CScript script;
         CScriptID script_id(*script_hash);
         CTxDestination inner_dest;
         if (store.GetCScript(script_id, script) && ExtractDestination(script, inner_dest)) {
-            if (auto inner_witness_id = boost::get<WitnessV0KeyHash>(&inner_dest)) {
+            if (auto inner_witness_id = std::get_if<WitnessV0KeyHash>(&inner_dest)) {
                 return ToKeyID(*inner_witness_id);
             }
         }

src/script/standard.cpp

@@ -261,9 +261,8 @@ bool ExtractDestinations(const CScript& scriptPubKey, TxoutType& typeRet, std::v
     return true;
 }
 
-namespace
-{
-class CScriptVisitor : public boost::static_visitor<CScript>
+namespace {
+class CScriptVisitor
 {
 public:
     CScript operator()(const CNoDestination& dest) const
@@ -300,7 +299,7 @@ class CScriptVisitor : public boost::static_visitor<CScript>
 
 CScript GetScriptForDestination(const CTxDestination& dest)
 {
-    return boost::apply_visitor(CScriptVisitor(), dest);
+    return std::visit(CScriptVisitor(), dest);
 }
 
 CScript GetScriptForRawPubKey(const CPubKey& pubKey)
@@ -320,5 +319,5 @@ CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys)
 }
 
 bool IsValidDestination(const CTxDestination& dest) {
-    return dest.which() != 0;
+    return dest.index() != 0;
 }

src/script/standard.h

@@ -9,10 +9,8 @@
 #include <script/interpreter.h>
 #include <uint256.h>
 
-#include <boost/variant.hpp>
-
 #include <string>
-
+#include <variant>
 
 static const bool DEFAULT_ACCEPT_DATACARRIER = true;
 
@@ -211,7 +209,7 @@ struct WitnessUnknown
  *    (taproot outputs do not require their own type as long as no wallet support exists)
  *  A CTxDestination is the internal data type encoded in a bitcoin address
  */
-typedef boost::variant<CNoDestination, PKHash, ScriptHash, WitnessV0ScriptHash, WitnessV0KeyHash, WitnessUnknown> CTxDestination;
+using CTxDestination = std::variant<CNoDestination, PKHash, ScriptHash, WitnessV0ScriptHash, WitnessV0KeyHash, WitnessUnknown>;
 
 /** Check whether a CTxDestination is a CNoDestination. */
 bool IsValidDestination(const CTxDestination& dest);